"Rhamnolipid biosurfactants from Brassica carinata oil: synthesis and characterization"

Bio-based industries frequently produce by-products that can be used as low-cost substrates in fermentation processes. Brassica carinata oil, used as substrete in biodiesel production, was employed in our previous studies to synthesize polyhydroxyalkanoates (PHAs), biodegradable polymers, which can be used in place of synthetic plastics. Brassica carinata oil exceed can be used as carbon source not only in PHA synthesis but also in rhamnolipid biosurfactant production. In this study, we showed the production of rhamnolipid biosurfactants by P. aeruginosa L05, using Brassica carinata oil as carbon source. Growth conditions and production optimization were performed by modulating several nutritional parameters, as described in our previous studies, in which we used the major by-product of biodiesel production, glycerol, for the rhamnolipid synthesis. Rhamnolipids were extracted with ethyl ether and were analyzed through 1 and 2D NMR spectroscopy. Unlike the rhamnolipids production by glycerol, that shows the prevalence of dirhamnolipids and a minor amount of monorhamnolipids, the production by Brassica carinata oil shows the dominant presence of monorhamnolipids.